Abstract:
Silicon dioxide nanoparticles (SiO2 NPs) are now commonly used in many felds (material packing, adhesive and sealant,
textile, bactericide, catalysis, agriculture and food, lubricating oil additives, biomedical applications, rubber, etc.). The
intensive use of nanoparticles in various felds today brings along the need for determining their possible toxic efects. In
this context, the present study aims to identify the median lethal concentration (LC50) of spherical and 22 nm-sized hydro philic amorphous SiO2 NPs, to determine the efects of SiO2 NPs on total hemocyte count (THC), and hemocyte viability
in Galleria mellonella (Lepidoptera: Pyralidae) larvae as a model organism. For this purpose, SiO2 NPs were given to the
larvae by the force-feeding method. After a 240-h treatment, LC50 was 411.93 μg/10 µl and LC90 was 829.10 μg/10 µl for
the force-fed larvae according to the probit assay. To investigate the efects of diferent doses of SiO2 NPs (10-180 μg/10 µl),
seventh instar larvae were fed by force-feeding method. The efect of SiO2 NPs on the THC and hemocyte viability in larvae
was determined by counting under the optical microscopy for 48-h following the force-feeding treatment. The obtained data
showed that the THC of larvae exposed to 60 and 100 μg/10 µl SiO2 NPs treatments resulted in a signifcant decrease in 48-h
when compared with the control group. According to the results of hemocyte viability performed by trypan blue viability
test, the percentages of the dead cells in the 100 (15.66%) and 180 μg/10 µl (17.94%) SiO2 NPs groups were higher than
that in the control group (2.92%) at the end of 48-h. This increase in the percentage of dead cells was statistically signifcant
when compared to the control group.